Underreamer for oil-wells.



M. H, DUNN. UQDERREAMEI: F03?. GIL WELLS. APPLICATION FILED DEC-1.9.1913. 4 w? l l ign, iig@ f s Patented Deo. 22, 1914. g5; ZSHBBTSASHEBTL M. H. DUNN.

UNDBRREAMEH Pola ou, WELLS.

APPLICATION FILED DEO. 19, 1913.

Patented Dec. 22, 1914.

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2 SEEETSASHEET 2.

Dwitmeowo Moses le. DUNN, or :tos ANGELES, cnmrormrs.

unnnnnnnnnn ron OIL-WELLS.

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Specification of Ietters Patent.

Patented Dec. 22 1314.

Applicetion filed December 19, 1913. Serial No. 807,666.

and inexpensive. underreamer, of few parts,v

having. bite ccperating with each other and with the steelt or body of the underreamer in an improved manner; further, to provide a springA codperating with both of .the bits in an improied manner whereby they, are spread. substantially equal spring tension and arranged and combined' `with the steel; or body in such. manner that the spring is housed and protected' without danger" of 'damage thereto.

the foregoing,- and othen, ob}ects in view, the invention consists of those im proved features and new combinations of parts set forth fully hereinafter.

.ln the accompanying drawings: Figure 1 is a side elevation, the bits being retracted; Fig. 2, `a similar view with the bits drawn down; `lig. 3, a view taken at right angles to Fig. 2; Fig. 4, an end view of the body the bits being removed; Fig. 5, an enlarged longitudinal section when the parts are in the condition shown in. Fig. l; Fig. 6, a similar view taken at right angles to Fig..

:3; and Fig. 7, an enlarged detail view of the bits detached andin theirnormal relaofthe bits and draws the bits upwardly,

tive positions.

The stock or body 1 is provided with"a slot 2 extending therethrough from side to side. The lower end of the slot is preferably closed by the bridgeportipn 3', but I do not limit myself to the provision-of this bridge, as the underreamer will operate satisfactorily without such bridge.

Upwardly undercut hinging abutments 4 are provided on the body and the lower end of the latter has vdouble inclined impact abutments 5 6, for each of the bits 7.

The bits 27 have double inclined contact. abutments 8, 9, whose angles substantially conform to Ithe abutments 5, 6. he abutments 5, 6, extend completely crossA the lower endof the body 1 save where inter-l cepted by the slots 2 fThe abutments 8, 9, of the bits 7 Acorrespond in length, respectively, to the abutments 5, 6, with which they are adapted to contact. These abut- ,ments receive the greater part of the blow bits engage. The Shanks 11 of the bits slide in the slots i2 yand are provided with longitudinally extending ribs 12 which, by their engagement with the casing of the well, collapse or force the bits toward each other. The ribs are from one to three and one-half inches wide according to the, size of the underreamer.

The inner faces of the Shanks. 11 are p vided, with elongated eyes 13. which l' side by side within the slots2 and through these eyes extends a pin or bolt leby. which the hits are pi-votalliyI connected at their upper ends wid; adaptability to slide up and down 1n relation to the pin or bolt 14. The pin or bolt 14, in connection with. the eyes-18 and the abutments 4 and ends. 10, constitutes a pivotal or hinging connection/for the bits. The provision of the abutments 4 and ends 10 relieves the' pin 14 of a very large amount of shock and strainto which it would otherwise be subjected.

On their inner faces the Shanks 11 are pro vided with lugs 15 having concaved lower faces 16.

A pin or member 17 bridges the slot 2 and around this pin is coiled a spring 18 whose bent ends 19 engage the concaved surfaces 16, whereby the tension of the single spring is exerted on both of the lugs 15 and on both maintaining the abutments 8, 9, in contact with the abutments 6, 5, and the abutments 10 in contact with the abutments 4. The pin- 14 is then in the lower ends of the eyes 13.. The parts in their retracted condition above described, are adapted for underreaming.

Each of the bits is provided with a recess 2O for the reception of a hook, by which tle bits may be pulled down against the tenu'sion of the spring, when it is' desired to insert the tool in .the casing. Immediately the tool'is .inserted in the casing, the ribs 12, byengagement with the walls of the casing,

keep-thebits pressed toward each other and disposed in their lower position. The 4pin 14 is then in the u per ends of the eyes 13:7

When the lower en of the casing is reached,

' the disengagement of the ribs 12from the' casing, permits the spring to act which thereupon draws the forces them outwardly.

bits upwardly and The spring, eyes and lugs being contained within the body, The abutments 5, of the impact or are protected from ingury. 6, 8, 9 take the greater part blou7 and relieve the pin 14 therefrom, While the provision or" a single pin and spring parts.

minimizes the number of The single pin 14, by connecting the bits together, minimizes the danger of loss or one o the bits.

I am aware that modifications of structure could be resorted to in carrying out the invention and l do not, theuefore, self to the details herein limit iny- -,et forth except Where specified in the claims. y

Having thus described my invention, what claim as new andv desirfto secure by Letters Patent,

l. In an underreamer, the combination with a body orstockl o a pair of bits, a'

common loose or lost motion pivotal connection between the bits and the body, and

spring means cominciato both of the bits.

adapted for both retraeting and spreading l them.'

2. In an underreamer, Awith a body,

gitudinally n the' combination of a pair of plvotally and lonmovable bits, and a spring cooperating ,With both of the bits and radapted to both retract them vlongitudinally and spread them laterally.

3. In an underreamer, the combination with a body, of a. pair ofpivotallyand longitedinally movable bits, and a single coiled spring Whose ends cooperate with the re-v 5. In an underreanier,l the combination with a body, of bits having Shanks provided with elongated eyes, a single pinpassing through said eyes and eonneetingtjhem to the body, and a single spring. veoperating with the bits and adapted lto spread and re` tract them. v

In testimony whereof, hereunto ali signature in presence of two witnesses.

` 1 MUSEES H. DUNN.

Witnesses:

OBEN Lrnn'rz,

L. W. Gagnon. 

